The present invention relates generally to apparatus for applying foamed treating material and more particularly to such apparatus for applying foamed treating liquor to a flat width of traveling textile substrate of the non-woven, non-knitted type.
Various apparatus are known for applying foamed treating liquor to a flat width of a traveling textile material of knitted or woven type, examples of such apparatus being disclosed in Clifford and Zeiffer U.S. Pat. No. 4,237,818, and Clifford and Turner U.S. patent application Ser. No. 299,533, filed Sep. 4, 1981, both commonly assigned herewith. Typically, such apparatus employs some form of foam applicator across which the textile material is pulled by driven rollers, which is inappropriate for use in applying treating liquor to textile materials of the non-woven, non-knitted type (hereinafter referred to generically by the common industry term "non-woven" to designate any sheet-like or web material bonded together substantially only by cohesive forces) which materials lack the structural integrity to resist structural damage thereto by the pulling action exerted thereon by the driven rollers of such apparatus.
Accordingly, special apparatus is necessary for the liquor treatment of non-woven materials. Presently, the apparatus available for this purpose employs moving screens or belts of open-work or other permeable construction on which a non-woven web is transported to and from a liquor applicator which is arranged to spray the desired liquor on the web. Several operational and environmental disadvantages are inherent in the use of this type of apparatus. As will be understood, the liquor employed in many cases is a binder or a resin which will necessarily be oversprayed on and adhere to the belt or screen impairing its flexibility and permeability and, in some cases, causing difficulty in the proper tracking of the belt or screen. Further, the spraying technique, even under conditions of overspraying of the treating liquor, generally is ineffective to achieve a desired degree of penetration of the treating liquor into the web and, for this reason, it is customary to perform the spraying operation twice respectively to each side of the web or to apply a vaccuum force through the belt to draw the sprayed liquor into the web. As will be understood, the spraying technique inherently creates a contaminated atmosphere in the vicinity of the applicator and thereby poses a health hazard. Further, the oversprayed liquor which accumulates on the belts and screens and otherwise in the vicinity of the applicator must periodically be washed from the surfaces affected, creating waste water treatment problems. As will be understood, all of these problems contribute to substantially increase the capital investment and operational costs in performing such non-woven treating operations.
In contrast, the present invention provides an apparatus for applying foamed treating liquor to a non-woven textile substrate by which the substrate is contactingly engaged by and compressed against an applicator nozzle for uniform application to and penetration into the substrate of the liquor without significant emission of liquor into the surrounding atmosphere or the adherence thereof onto any operational element of the apparatus and, further, without structurally damaging the substrate.